Many metals readily react with halogen gases at elevated temperatures to form metal halides. Some metal halides exhibit low melting points and some even sublime at relatively low temperatures. As a result, metallic alloys that form metal halides may suffer high-temperature corrosion. Industrial environments often contain halogen gases. Therefore, reactor vessels that are resistant to high temperature halogenation attack are often required.
Hydrogen (H2) and silicon-tetrachloride (SiCl4) are used at temperatures between 950° to 1150° F. (or 510° to 621° C.) and at a relatively high pressure to produce solar grade silicon. The reaction between hydrogen and silicon-tetrachloride results in the formation of hydrochloric acid gas, HCl(g). The equilibrium between hydrogen gas and hydrochloric acid gas defines a partial pressure of chlorine gas (PCl2) that can lead to high temperature chloridation attack on reactor vessel which is usually made of metallic alloys. Therefore, there is a need to determine the extent of halogenation of metallic alloys in an environment containing halogen gases.